Hydraulic shock absorber



Feb. 22,A 1938. A. B. CASPER HYDRAULIC SHOCK ABSORBER Filed March l5, 1937 2 Sheets-Sheet 1 Jrg-1 Feb. 22, 1938. A. B. CASPER HYDRAULIC SHOCK ABSORBER Filed March l5, 1937 2 Sheets-Sheet 2 affitti Illini nl! I Il iuvv v f f YE F A/THONY @AeA/5e.

Patented Feb. 22, 1938 t l l UNITED STATES PATENT OFFICE HYDRAULIC SHOCK ABSORBER Anthony B. Casper, Buffalo, N. Y., assignor to Houde Engineering Corporation, Bnilalo, N. Y., a corporation or New York Application March 15, 1937, Serial No. 130,848

'Z Claims. (Cl. 188-88) This invention relates to hydraulic shock abbeing connected at its outer end with the upper sorbers, particularly to the direct acting type of end of the cylinder space by a port I6. The Wall A shock absorber in which cylinder and piston l has other bosses Il extending longitudinally structure elements move relatively longitudinally between the wall and the tube I3, these various for displacement of hydraulic iiuid when the bosses holding the tube properly spaced from the shock absorbers are in service. wall. The comparatively narrow bosses I'l have An important object of the invention is to propassages I8 therethrough for connecting the duce a shock absorber of this type the body strucspaces between these bosses and between the ture of which is cylindrical when viewed from bosses and the Wide boss I4, these communicat- 10 the outside but whose cylinder element is in the ing spaces forming a reservoir I9 for hydraulic form. of a casting having a cross-sectional shape uid, this reservoir space being connected at its 10 for cooperation with a surrounding tubular wall inner end With the inner end 0f the Cylinder to provide iluid reservoir space along one side of Space by a pel't 2G. the cylinder element and a ow passageway along The piStOn Structure comprises a piston 2| one side thereof for oW of displaced uid during and a piStOh I'Od 22 extending OlitWaI'dly through 15 rebound stroke of the shock absorber, the bore 23 of the outer head I2. The piston re- A further important object is to provide imceives the reduced end 24 of the piston rod and is proved structure and arrangement for valving clamped thereto by means of-a hut 25. The pismeans for metering the rebound i'luid ow and t0n hel/S DOItS 25 therethrough Controlled by a with the valve means readily adjustable from Valve 27 in the form Of ah annular plate SUI- 20 the exterior of the shock absorber for accurate rounding the hub 0f the DiStOIl and vertically. fluid now metering and control. l shiftable thereon, the movement being limited by The invention also embodies other features of an abutment plate 23 clamped between the Disconstruction and arrangement, all of the features t0n and the piston rod. 25 of the invention being embodied in the struc- The inner cylinder head EI has a cross bore 25 ture disclosed on the drawings, in which draw- 29 extending diametrally across the inner end ings: of the cylinder, one end of thisbore being con- Figure 1 is a side elevation of the shock abneeted by the passage 30 With the inner end 0f sor-ber; the channel I5. The other end of the cross 30 Figure 2 is an enlarged sectional view on plane bOre 29 iS elOSable by a Dlller 3l having threaded 30 II-II of Figure l; engagement in the bore end. Between the plug Figure 3 is a, section on plane 111-111 of Figand the passage 30, the bore receives a bushing ure 2; 32 provided with a longitudinally extending slit Figure 4 is a diametral section of the lower end 33 fer COmInUIlCatiOn between the bore 29 and 5 of a shock absorber showing a modied valving the inner end 0f the Cylinder. Fitting in the f arrangement; bore of the bushing is a cylindrical valve plug Figure 5 is a diametral section 0f the lower end 3d threaded at its outer end for engagement with of a shock absorber showing still another valvthe threaded Outer end 0f the bushing, aS inding arrangement; and cated at 35, so that when the valve plug is turned Figure 6 is a section on plane VI-VI of Fig' its resulting axial movement Will cause its inner 40 ure 5. end to overlap the slit 33 more or less for de- In the shock absorber of Figures 1 to 3, the lining a restricted Orifice passage 36 between the cylinder structure comprises the cylinder wall end of the valve and the inner end of the slit.

I0 having the inner and outer closure heads II Upon remOVal 0f the plug 3l. the Valve plug will and I2. The wall I0 and the closure head II are be accessible for adjustment, and to facilitate 45 preferably part of a single casting and the outer such adjustment the valve plug may be provided head I2 being a separate casting detachably seat its outer end with a cross slot 3l for receivcured by threaded engagement with the wall Ill. ing a screw driver or other suitable tool by which Surrounding the wall I0 coaxial therewith and the valve plug may be readily turned.

spaced therefrom is a tube I3 seated at its ends The head II has the annular channel 38 surin the heads II and I2 respectively. The wall I0 roundingthe bushing 32, this channel being open has a comparatively wide boss I4 extending lonto the inner end of the cylinder and the orice gitudinally between the Wall I0 and the tube I3 slit 33 communicating 'with the channel to be and in its outer side having the channel I5 of thus in communication with the inner end of the which the tube forms the outer wall. this channel cylinder. A boss 39 provides a uid inlet passage 55 to the channel 38 through which hydraulic fluid may bev charged into the cylinder and into the reservoir in order that the cylinder may be at all times iilled with fluid and the reservoir may have an ample supply of replenishing fluid. The

illler passage is closable by a threaded plug 48.

The head II terminates in an eye 4I by which the cylinder structure may be `secured to a support such as the axle of an automotive vehicle with whose springs the shock absorber is to be associated. The piston rod has secured to its outer end, preferably by threading, a fitting 42 which has an eye 43 by means of which the piston structure may be secured to a support such as the chassis of the vehicle.

'I'he outer closure head I2 for the cylinder has a recess 44 for receiving suitable packing structure 45 intimately engaging the piston rod to prevent escape of leakage fluid to the exterior of the shock absorber; any fluid which may leak through the piston rod bearing bore 23 being wiped by the packing and-retained in the recess 44 for return to the outer end of the reservoir space through a passageway 46.

Clamped to the piston rod by the fitting 42 is a disc 41 having the peripheralilange 48 which receives the outer end of a tubular shield 43 which surrounds the tube I3 and has secured to its inner end an annular housing 50 for containing packing material 5I engaging the tube I 3 to act as a shield against the entrance of dust or other foreign matter to the shock absorber working parts, the shield structure acting also as a guide for the piston structure during service of the shock absorber.

Describing the operation, during compression movement of the vehicle spring the piston structure will move the piston toward the inner end of the cylinder, fluid displaced from the inner end of the cylinder lifting the valve 21 and flowing through the piston ports 26 to the outer end of the cylinder. Owing to the volumetric differential at opposite sides of the piston on account of the volume of the piston rod, the outer end of the cylinder cannot accommodate all of the fluid displaced from the inner end of the cylinder and the surplus fluid will therefore flow through the port 26 into the reservoir space I9, and this port may be of a size to afford shock absorbing resistance to the surplus uid flow.

During rebound movement of the vehicle springs and outward movement of the piston, the valve 21 will close the piston ports 26 so that the fluid displaced from the outer end of the cylinder must flow through the port I6, the channel I5, the passage 30, valve bushing 32, and through the orifice passage 36 into the inner end of the cylinder, the orifice passage metering this flow and determining the shock absorbing resistance thereof. On account of the volumetric differential, suction will be created in the lower end of the cylinder as the piston moves outwardly but this suction is broken by ow of hydraulic fluid from the reservoir through the passage 26 into the inner end of the cylinder, and such fluid ow also replenishes the cylinder with hydraulic uid. By removing the plug 3|, the valve 34 may be readily set for the proper size of the orifice 36 for the desired shock absorber resistance during rebound movement of the vehicle springs. The arrangement is such that the bushing 32 with the valve plug therein may be readily inserted into the bore 29 or withdrawn therefrom. Before the valve structure is inserted, the valve may be adjusted for the desired orifice size, and then if amasar a further adjustment is necessary after the shock absorber is in service position on a car, the plug 3| may be removed and the valve given its final setting. f

,In the modified arrangementof Figure 4, the cylinder 52 may have the same cross-sectional formas the cylinder structure of Figure 2, and as shown by Figure 3, to provide reservoir space 53 and the rebound fluid flow channel 54 between the cylinder wall and the tube 55. 'I'he inner cylinder head 56 is a separate structure and is secured to the inner end oi' the cylinder by threading engagement of its threaded boss 51 into the cylinder end, the cylinder end having the ange 58 which is received by the inner end of the tube 55, and the head 56 having the annular flange 53 engaging the outer side of the tube.

The piston rod 66 has secured to its inner end the piston 6I having the ports 62 therethrough controlled by the annular disk valve 63. 1

The cylinder head 56 has the axially extending recess 64 continuing through the boss 58 for communication with the inner end of the cylinder. This axial passage is intersected by the cross bore 65 in the head, the inner end of this bore being in communication with the inner end of the channel 54 by way of the passage 66 extending through the head and the cylinder flange 58. Between the passage66 and the axial space 64, a seat bushing 61 is mounted in the bore 65 and receives the cylindrical end 68 of a valve plug 69 whose head 10 has threaded engagement in the threaded outer end of the bore 65. The valve end 68 is bored to leave a thin wall which has one or more longitudinal slits 1I surrounded by the bushing 61, the distance of the inner ends of the slits outwardly from the outer edge of the bushing determining the size of metering orifices 12. The outer end of the bushing is preferably bevelled so as to present a sharp edge at the slits in order that the orifices may function as sharp edge orifices for metering the fluid flow substantially independently of viscosity changes in. the liquid. The outer end of the bore 65 is closable by a plug 13 where access may be had to the valve for adjustment thereof, the valve head being provided with slots 14 for application of a suitable instrument for turning the valve, and a friction member 15. may be inserted in the slot to frictionally hold the valve in adjusted position. A

During compression stroke of the vehicle spring with which the shock absorber is associated, displaced uid flows from the inner end of the cylinder to the outer end thereof through the piston ports 62, the surplus fluid which cannot be received by the outer end of the cylinder flowing into the reservoir space 53 through the passage 16 provided at the inner end of the cylinder Wall 52. During rebound movement of the vehicle spring and outward movement of the piston, the valve 63 closes the ports 62 and the iiow will be confined to a path extending from the outer end of the cylinder, through the channel 54, passageway 66, bore 65, the bore of t'he valve end 68, and through the restricted orifice passage 12 into the space 64 and from there to the inner end of the cylinder, the restricted orifice passage 12 metering this fiow for proper shock absorbing action of the shock absorber -during vehicle spring rebound movement.

The valve structure can be readily inserted into the head bore I3 through the outer end thereof, and the valve seating bushing 61 may be readily inserted into the bore through the inner amasar end thereof which end is then closed as by means of a plate 11.

In the modied arrangement of Figs. 5 and 6, the cylinder 18 is shown in the form of a tube and is surrounded by a tubular wall 19 having on its inner side the longitudinally extending bosses 80 and 8|, and 82, which abut at their inner ends against the cylinder tube so as to provide reservoir space 83 and a uid channel 8|. At its inner end the structure 19 terminates in a head 85 and the structure 19 and the head may be part of an integral casting, the head having a cylindrical recess 86 for receiving the inner end of the cylinder tube 18. The head 85 has the cross bore 81 extending diametrally at the inner end of the cylinder and communicating therewith. Within the bore is the bushing 88 providing a seat for the valve plug 89 which has threaded engagement in the outer end of the bushing. The bushing has a longitudinally extending slit 90 connecting the interior of the bushing with the inner end of the cylinder and this slit is overlapped more or less by the valve plug to define a restricted orifice passage 9| between the inner end of the slit and the inner end of the valve plug. The outer end of the bore 81 is closable by a plug 92 having threaded engagement therein and when the plug is withdrawn the valve may be readily adjusted for the desired size of the orifice passage SI. The inner end of the bore 81 is connected with the channel 84 by a passage 93.

The piston rod 94 carries at its inner end the piston 95 which has the ports 96 therethrough controlled by the annular disk valve 91, the inner end of the cylinder being connected with the reservoir space 83 by a passage 88.

During compression movement of the vehicle spring and inward movement of the piston, the displaced uid ows from the inner end of the cylinder through the ports 96 to the outer end of the cylinder, surplus uid flowing into the reservoir space through the passage 98. During rebound movement oi' the vehicle spring, the fluid displaced from the outer end of the cylinder flows through the channel 84 and passage 83 into the bore 87 and then through the restricted orifice passage 9i into the inner end of the cylinder, the orifice passage metering this ow for the desired shock absorber action.

The valve plug may be hollow, as shown, so that when the plug 92 is removed the shock absorber may be readily iilled or replenished with hydraulic fluid.

I have shown practical and eiicient embodiments of the various features of my invention but I do not desire to be limited to the exact construction, arrangement and operation shown and described as changes and modifications may readily be made without departing from the scope of the invention.

I claim as follows:

1. In a direct acting shock absorber, a cylinder structure, a pistonstructure comprising a piston and a rod extending therefrom to the exterior of the cylinder structure, a tubular wall surrounding the cylinder structure, means between said wall and cylinder structure extending longitudinally thereof and deiining a reservoir space and a uid ilow channel, means defining a cross passage at the inner end of said cylinder, the inner end of said cross passage being connected with the inner end of said channel and the outer end of said channel being connected with the outer end `of the cylinder, and adjustable permanently open lvalve means in said cross passage for restricting the communication thereof with the inner end of the cylinder and for metering the iiow of the fluid displaced from the outer end of said cylinder and through said channel during rebound movement of the vehicle springs with which the shock absorber is associated.

2. In a direct acting hydraulic shock absorber, a cylinder, a tubular wall surrounding said cylinder, means between said wall and cylinder extending\longitudinally thereof and defining a reservoir space for hydraulic fluid and a channel for displaced iuid ow, means defining a cross passage at the inner end of said cylinder, said cross passage being connected with the inner end of said channel and the outer end of said channel being connected with the outer end of the cylinder, a bushing within said cross passage having an orifice slit connecting said passage with the inner end of the cylinder, a valve adjustable in said bushing for overlap of said slit to denne a restricted orifice passageway for metering the flow of the iluid displaced from the outer end of said cylinder and through said channelto theinner end of the cylinder during rebound movement of the vehicle spring with which the shock absorber is associated.

3. In a direct acting hydraulic shock absorber,

a cylinder having a closure head at its inner end provided with a cross bore extending diametrally relative to the cylinder end, a wall surrounding the cylinder coaxial therewith, partitions extending longitudinally between said cylinder and said surrounding wall to define a channel connected at its outer end with the outer end of the cylinder and at its inner end with the inner end of said cross` bore, means defining a metering port between said cross bore and the inner end of the cylinder, and a valve adjustable in said cross bore for controlling the size of said port, a piston movable in said cylinder, said port metering the uid flow by way of said channel from one side of the piston to the other during outward and inward movement of the piston in the cylinder.

4. In a direct acting hydraulic shock absorber, inner and outer closure heads for said cylinder, an outer wall extending between said heads concentric with said cylinder but spaced therefrom, said inner head having a cross bore communieating with the inner end of the cylinder, partition walls extending longitudinally between said cylinder and said outer wall for dening hydraulic duid reservoir space and a fluid iiow channel, means connecting the outer end of said channel with the outer end of the cylinder and means connecting said channel with the inner end of said cross bore, a piston movable in said cylinder and having valving means thereon for controlling the iiow of iiuid from one side of the piston to the other during inward movement of the piston in the cylinder, and adjustable valve means in said cross bore for metering the fluid ow through said channel from the outer end of the cylinder to the inner end thereof during outward movement of the piston in the cylinder,

said reservoir space being connected with the inner end of the cylinder for the i'low thereinto 0f replenishing hydraulic fluid.

5. In a direct acting hydraulic shock absorber, inner and outer coaxial walls spaced apart radially, inner and outer heads closing the ends of said walls, said inner wall forming a cylinder between said heads, a longitudinally extending boss on one of said Walls and extending radially between said walls, said bom having a channel therethrough, a cross bore in the inner head, means connecting the outer end oi' said channel with the outer end of the cylinder and means connecting the inner end thereof with the inner end of said cross bore, a valving assembly within said cross bore for metering the iluid flow by way of said channel from the outer end of the cylinder tothe inner end thereof during outward movement of said piston in said cylinder, said piston having ports therethrough and valve mechanism entially spaced apart partition Walls extending longitudinally between said coaxial walls and between said heads, the inner wall of said coaxial walls providing a cylinder, the space between two of said partition walls providing a channel having connection with the cylinder at the opposite ends thereof, the space between the remaining partition walls providing a fluid reservoir having connection with the cylinder at the inner end thereof. a piston structure operable in said cylindex', and a valve assembly for controlling the ow through said channel and from one side of the piston structure to the other during movement of the piston structure in said cylinder.

7. In a direct acting hydraulic shock absorber, inner and outer coaxial walls spaced apart radially, innerand outer heads closing the ends ot said wall, said inner wall forming a cylinder between said heads, a piston structure operable within said cylinder, partition walls circumferentially spaced between said coaxial walls and extending longitudinally between said coaxial walls and said heads, the space between two oi said partition walls providing a channel having communication with the ends of the cylinder, the space between the remaining partition walls providing a uid reservoir communicating with the 

